Knife unit for meat cutters



May 27, 1941.

I D. o. BECKNER KNIFE UNIT FOR MEAT CUTTERS Original Filed Feb. 24, 1939Patented May 27, 1941 UNITED STATES TENT orrlo Divided and thisapplication October H, 1939, Serial'No. 298,933

5 Claims.

My present invention relates to plural-bladed rotary knife units,including the knife or cutter proper and an associated die plate,particularly for meat cutters, and aims to provide extremely durable,non-corrosive and otherwise improved units of the character referred to.This application: a division of my Patent No. 2,176,867 dated October24, 1939.

In the drawing illustrating by way of example one embodiment of theinvention and certain steps for practicing its method-- Fig. 1 is asection through the delivery end of a meat cutter having a knife unit ofthe invention installed therein; 7

Fig. 2' is a plan of a core, blank or forging for the knife;

' Fig. 3 illustrates an early stage in the formation of the knife,showing in plan certain stainlesssteel members in position for unitingwith the core of Fig. 2;

Fig. 4 is a plan view ofthe knife of Fig, 3 at an intermediate stage;

Fig. 5 shows in plan the knife of Figs. 3 and 4, inverted and insubstantially complete form;

Figs, 2a, 3a., 4a and 5a are enlarged cross secknife, after grinding andpolishing to the extent desired and Fig. 6a is an enlarged end View ofone arm of said finished knife.

Referring to the drawing in more particular, in Fig. 11 have representedthe delivery end of a typical meat cutter or grinder, including the mmn.head '3 housing the feed. screw 8 and having a retaining cap 9 threadedontov its outer edge. The feed screw 8 has an outwardly projectingcentral shaft ill with a non-circular portion l l for receiving theknife, the latter indicated as a Whole by the numeral 5. The knife has acentral correspondingly shaped aperture fitting said. noncircularportion of the shaft, so. that the knife is caused to rotate with thefeed screw 8.

outwardly of the knife 55 is a stationary perforateplate. or die elementIt of novel construction. Desirably it is composed of a specialextremely hard stainless steel, and. has formed integrally in one piecewith it a central boss 13 apertured to receive and form a bearing forthe outer cylindrical portion of the shaft it]. This die plate I2 isclamped in. fixed position in the head I, by the threaded cap 9, beingheld against turning as by a notch I4 at some peripheral portion of theplate engaging a correspondingly shaped projection on thehead. Theplatehas a multiplicity of apertures l2a drilled. through it, the meatbeing forced through the apertures by the feed screw and. out off by theknife rotating across them with its cutting edges contacting the inneror rear face of the plate.

Referring now more particularly to Figs. 2 to 6', and first to Fig, 2,"I have there shown inplan a core, blank or forging indicated as a Wholeby the numeral: l6. feet a base for the composite knife as a whole. Itis forged or otherwise formed from ordinary relatively low-grade steel,such'as any good coldrolled steel, having substantial toughness, ascontrasted with brittleness, but relatively soft and henceunsatisfactory for the formation of cutting edges which are subject tosubstantial wear.

Said core comprises a hub I! having a noncircular aperture to conform tothe like-shaped portion II of the meat-cutter shaft In, Fig. 1.

The hub H has formed integrally with it a plurality of lateral arms 18extending in a generally radial direction, one arm for each of the.blades of the knife. Any plurality of. blades and arms. may be employed,usually at least three, but in most instances I findv that four suchelements,

disposed substantially at right angles to each other, are preferable;The arms l8 may be variously shaped in cross section; see for exampleFig. 2a. and the other sectionalviews. one corresponding longitudinalside made approximately straight and flat, as indicated at I9.

As described inmy earlier application, this core or forging It ispositioned substantially flatwise on a welding table, with either faceup, that shown in Figs. 2, 3 and4 being the face corresponding to theouter or front. face of the finished knife. As illustrated in. Fig. 3, Iapply along each of the arms it, in abutting relation to their fiat sidefaces it, a, rod or bar 2i] of a high-grade hard stainless steel. Asclearly seen in the corresponding enlarged section, Fig, 3a, these rodsare some- What larger in section than the arms of the core, and have apolygonal or other cross sectional shape herein rectangular, to providealong at least one longitudinal portion an angular corner section 2iadapted to constitute the cutting edge element for the correspondingfinished blade.

With the parts positioned as in Figs. 3 and 3a the material at theupperand inner longitudinal portion of each stainless-steel rod 20, inwardlyfrom the corner sections 2!, is subjected This element provides in ef-Each has to a fuse welding operation in the course of which it is flowedover onto and across the then upper face of the adjacent arm l8. Duringthis operation said outer corner portions 2| of the stainless-steel rods20 are kept intact, in their original condition. The resultingformation, wherein the arms l8 of the core and the juxtaposedstainless-steel elements 20 have been united into embryo blades 22,. isillustrated in Fig. 4 and Fig. 4a. In the several sectional views theoriginal shape of the stainless-steel rods is indicated by the dottedlines.

The partly formed knife of Fig. 4 is then inverted and positioned on thewelding table with its other face upward, as represented in Fig. 5 andas disclosed in said earlier application. The then upper longitudinalportions of the stainlesssteel rods 20, again excepting the cornerportions 2|, are similarly fused and flowed across and about theadjacent portions of the corresponding arms l8, so as substantially toenclose the latter, and outer portions of the hub I! if desired, in acoating of said non-corrosive material; see particularly Fig. 5a.

It will be particularly noted that in any and all stages thestainless-steel material along the corner portions 2| of the rods is nottouched but remains unchanged from its original condition and shape.Hence with the completion of the operation illustrated in Figs. 5 and 5athe knife l5 as a whole is substantially complete, subject only to suchfinishing byway of grinding and polishing as may be desirable. Sincesaid corner portions 2| of the stainless-steel rods have not been fusedor melted they are entirely free of irregularities such as blow holeswhich are likely to result from welding. Accordingly they present auniform surface and edge available as the cutting element for theblades, with but a minimum of grinding or finishing to conform them tothe inner face of the die plate [2 with which they are to cooperate.

Fig. 6 illustrates a completed knife, with its outer or front faceupward, as in Figs. 2 to 4. The ends of the composite blades 22 may berounded off as there shown, making them uniform and giving the knife anattractive appearance. The leading edge portions 2| of the severalblades 22, provided by the intact corner portions of the stainless-steelrods, are ground to any extent necessary to sharpen their edges and truetheir front surfaces into a given plane, affording flat riding faces 23for moving over and in contact with the die plate l2. The attractiveappearance of the knife may be further improved by polishing, giving ita bright surface and making it easy to clean.

In the resulting knife substantially all surfaces which in operationcome in contact with the meat are rendered non-corrosive, so that theyare not affected by the acids of the meat, by the coating of stainlesssteel on the arms of the core or bas l6, completely along them to andonto the hub portion I! to any extent desired. The cutting andplate-engaging portions of the blades, being formed of the hardstainless steel, are extremely durable and in practice are found tostand up over long periods of use without sharpening or other attention.The composite knife, the method of making which as herein described andillustrated is claimed in my patent previously mentioned, is superior toone formed entirely of stainless steel of similar quality and hardness,due to the comparative brittleness of said material. Since the knife hasin effect a base of the relatively soft but tough steel, by reason ofthe core or forging I6, breakage of the blades is reduced to a minimum,the operating stresses and vibrations being largely absorbed by thecomparatively soft steel core. At the same time a substantial saving iseffected in the quantity of the relatively expensive stainless steelemployed, as contrasted with a cutter composed entirely of suchmaterial.

My invention is not limited to the particular embodiment as hereinillustrated or described, its scope being pointed out in the followingclaims.

I claim:

1. A rotary knife for a meat cutter, comprising a core including a huband a plurality of lateral arms, said core comprising a forging of arelatively soft tough steel, each arm of the core having along acorresponding side a relatively hard stainless-steel rod of originalpolygonal cross section and of which an outer longitudinal cornerportion provides a cutting edge element along the corresponding arm,other portions of each rod being disposed around its arm as a coatingsubstantially completely enclosing the latter and adjacentmeat-contacting portions of the hub, whereby the knife as a wholepresents to the meat a surface unaffected by the acids thereof and isequipped with cutting edge elements of extreme durability and sosupported and connected by the tough, relatively soft core that breakagetendencies under operating stresses and vibrations are reduced to aminimum.

2. In a meat cutter, a knife comprising a core element of relativelysoft steel including laterally extending integral arms each having onesubstantially straight side face, at corresponding sides, each armhaving along its said side face an edge-forming relatively hardstainless-steel bar of polygonal cross section and having the materialof said bar distributed as a coating substantially completely around thecorresponding arm from its outer end inward for at least a major portionof its length and with one original longitudinal corner edge section ofthe bar providing a cutting edge along the full cutting length of thearm.

3. A rotary knife for a meat cutter, comprising a hub and a plurality ofgenerally radial blades, each such bladeincluding a coextensivelongitudinal supporting core of a relatively soft tough steel and havinga substantially straight longitudinal side face, said core faces of theseveral blades being correspondingly disposed, and each blade alsoincluding a substantially enclosing coating of a relatively hardstainless steel material distributed from an angular-sectioned barthereof set along the straight side face of its core and welded thereonwith an intact longitudinal corner portion of said bar presenting thecut ting edge for the blade.

4. In a meat cutter, a knife unit comprising a one-piece perforate diplate element of superhard stainless steel, said plate element having,at one face only, an integral centrally disposed hub with ashaft-receiving bearing aperture, and a cooperating plural-bladed knifeelement comprising a core of relatively soft steel having a lateral armfor each blade, each arm having fuse welded thereon a substantiallyenclosing coating of a hard stainless steel derived from a juxtaposedbar thereof of polygonal cross section one edge and corner portion ofwhich is preserved intact to provide the cutting edge for the particularblade.

5. A rotary meat-cutter knife comprising a centrally apertured hub and aplurality of substantially radial arms each with a cutting edgeformation along its leading longitudinal edge,

said hub and arms constituted as a unit having 5 a core portion, forboth the hub and the arms, of a relatively soft tough steel, such coreportion of each arm having along the leading longitudinal edge thereof abar of relatively hard stainless steel having one longitudinal portion10 of angular form in cross section and disposed to tially completelyaround the corresponding arm from its outer end inward oversubstantially its full length and integrally uniting the cutting edgeformation thereof with said core portion.

DONALD O. BECKNER.

